Nucleus
A virus replicates its DNA in a cell when it infects the host
A virus will replicate within a host cell.
Viruses replicate by hijacking a host's cells. The virus inserts its own RNA sequence into the host cell's nucleus, forcing it to replicate the virus until the host cell dies.
Virus cannot replicate it self. It should enter into a host
Host.
It can reproduce if it infected a host cell!
Viruses replicate fast and mutate easily.
replicate
Ribosome
For a virus to replicate it must insert its own DNA into a host nucleus cell. This newly infected cell finds another host cell to replicate, and a viral infection is produced.
"True" viruses replicate by injecting their code into another executable program. Most likely, the "host" program is a commonly used application such as Microsoft Word so that this guarantees the virus is able to successfully replicate. When the infected program is executed, control diverts to the virus, which the copies and infects another program, and then returns control back to the host program. Long loading times for programs are a common sign of virus infections.